Firearm pin retainer plate and pivot pins

ABSTRACT

Firearm pin retainer plates and pins have a frame defining an internal space, a moving action part defining a bore and connected to the frame within the space, a pivot pin connected to the frame and to the action part such that the action part pivots with respect to the frame, the pivot pin having a cylindrical body portion closely received in the bore and defining a pin axis, the pivot pin having a first flat surface portion, a retention element connected to the frame within the space and having a first retention facility adapted to engage the first flat surface portion to prevent rotation of the pin with respect to the frame. The pin may have a second flat surface portion opposed to the first flat surface portion. The first retention facility may define a slot having opposed edges operable to engage the first and second flat surface portions.

This application claims the benefit of U.S. Provisional PatentApplication No. 62/336,817 filed on May 16, 2016, entitled“NON-ROTATIONAL HAMMER/TRIGGERPIN KIT FOR AK47 AND VARIANTS,” which ishereby incorporated by reference in its entirety for all that is taughtand disclosed therein.

FIELD OF THE INVENTION

The present invention relates to firearms, and more particularly to apin retainer plate and pins that prevents the pins from rotating withrespect to the receiver.

BACKGROUND OF THE INVENTION

The AK-47 is the most popular and widely used assault rifle in theworld. It is well known for its reliability under harsh serviceconditions, ease of use, and low production cost. The conventionaldesign uses a retainer spring in the form of a bent elongate wire tohold the hammer and trigger pins in the receiver. While the retainerspring is generally reliable, the retainer spring does not prevent thehammer and trigger pins from rotating, eventually leading to undesirablewear on the receiver pin axis holes that results in a loose fit.Furthermore, if the retainer spring does fail, the rifle becomesinoperable until the retainer spring is replaced, and trigger groupparts are vulnerable to being lost.

A variety of retainer plates have been developed to replace the retainerspring with a stronger part that is less vulnerable to failure.Furthermore, retainer plates make reassembly of the trigger group easiercompared to using the conventional retainer spring. Unfortunately,existing retainer plates do not prevent the hammer and trigger pins fromrotating. In addition, existing retainer plates require the safetyselector to be removed prior to installing the retainer plate, and somerequire the hammer and trigger with their respective pins to beinstalled before the retainer plate and safety selector are installed.Because some semi-automatic and all fully automatic AK-47 rifles requirethe safety selector to be installed before the trigger and hammer withtheir respective pins, many existing retainer plates are not compatible.

Existing products are used to provide an anti-rotation function for pinson firearms with external surfaces. These include the Gen 2 Non-RotatingTrigger/Hammer Pins provided by KNS Precision Inc. of Fredericksburg,Tex. These are used for AR-15 rifles and use pins that have ends formedwith a blade having flat surfaces analogous to the tip of a flat bladescrewdriver. An external retainer bar having a mating slotted cap(analogous to a slotted screw head) on one end to engage the bladeprevents rotation of the bladed pin, and the retainer bar is secured atits opposite end with a fastener to a tapped hole in the end of anotherpin. While effective for the AR-15 and similar designs with no operatingor mounting components on the exterior surfaces of the lower receiverwhere these anti-rotate components are connected, they are unsuitablefor other applications such as the AK-47 and its variants. Thesetypically require optics mounts to be mounted to the left face of thereceiver, and have a safety selector lever on the right side, preventingthe external mounting of anti-rotation components. Because the existingNon-Rotating Trigger/Hammer Pins have the flat blade section at the endso they can be engaged by the slotted cap, and the slotted cap isattached by external fasteners, this is not suitable for the AK-47.

Therefore, a need exists for a new and improved firearm pin retainerplate and pivot pins that prevents the pins from rotating with respectto the receiver and can be installed with the safety selector already inplace. In this regard, the various embodiments of the present inventionsubstantially fulfill at least some of these needs. In this respect, thefirearm pin retainer plate and pivot pins according to the presentinvention substantially departs from the conventional concepts anddesigns of the prior art, and in doing so provides an apparatusprimarily developed for the purpose of providing a pin retainer platewith pins that prevents the pins from rotating with respect to thereceiver and can be installed with the safety selector already in place.

SUMMARY OF THE INVENTION

The present invention provides an improved firearm pin retainer plateand pivot pins, and overcomes the above-mentioned disadvantages anddrawbacks of the prior art. As such, the general purpose of the presentinvention, which will be described subsequently in greater detail, is toprovide an improved firearm pin retainer plate and pivot pins that hasall the advantages of the prior art mentioned above.

To attain this, the preferred embodiment of the present inventionessentially comprises a frame defining an internal space, a movingaction part defining a bore and connected to the frame within the space,a pivot pin connected to the frame and to the action part such that theaction part pivots with respect to the frame, the pivot pin having acylindrical body portion closely received in the bore and defining a pinaxis, the pivot pin having a first flat surface portion, a retentionelement connected to the frame within the space and having a firstretention facility adapted to engage the first flat surface portion toprevent rotation of the pin with respect to the frame. The pin may havea second flat surface portion opposed to the first flat surface portionand the first retention facility may define a slot having opposed edgesoperable to engage the first and second flat surface portions. Theopposed flat surface portions may be parallel to each other. There are,of course, additional features of the invention that will be describedhereinafter and which will form the subject matter of the claimsattached.

There has thus been outlined, rather broadly, the more importantfeatures of the invention in order that the detailed description thereofthat follows may be better understood and in order that the presentcontribution to the art may be better appreciated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of the current embodiment of a firearm pinretainer plate and pivot pins constructed in accordance with theprinciples of the present invention installed in a rifle.

FIG. 1A is an enlarged view of circle 1A of FIG. 1.

FIG. 2 is a front isometric view of the current embodiment of thefirearm pin retainer plate and pivot pins of FIG. 1 showing therelationship with an installed safety selector.

FIG. 3 is a left side view of the current embodiment of the firearm pinretainer plate of FIG. 1.

FIG. 4 is an isometric view of the current embodiment of the pin of FIG.1.

FIG. 5 is a top isometric view of the current embodiment of the firearmpin retainer plate and pivot pins of FIG. 1 installed in a receiver.

FIG. 6 is a side enlarged view of the current embodiment of the firearmpin retainer plate of FIG. 1 showing how the rear fork snaps over thesafety selector pin to install the firearm pin retainer plate.

FIG. 7 is an isometric view of the current embodiment of the pins ofFIG. 1 installed in a receiver showing how the heads of the pins areaccessible from outside of the receiver.

FIG. 8 is a rear sectional fragmentary view of the current embodiment ofthe firearm pin retainer plate and pivot pins of FIG. 1 installed in areceiver.

The same reference numerals refer to the same parts throughout thevarious figures.

DESCRIPTION OF THE CURRENT EMBODIMENT

An embodiment of the firearm pin retainer plate and pivot pins of thepresent invention is shown and generally designated by the referencenumeral 10.

FIGS. 1-4 illustrate the improved firearm pin retainer plate and pivotpins 10 of the present invention. More particularly, the firearm pinretainer plate and pivot pins are shown installed in the receiver 100 ofa rifle 114 in FIGS. 1 and 1A, which is an AK-47 in the currentembodiment. A portion of the left sidewall 102 of the receiver iscutaway to expose the firearm pin retainer plate and pivot pins. Therelationship between an installed safety selector 104 having a selectorpin 106 and the firearm pin retainer plate and pivot pins is shown inFIG. 2. FIG. 3 shows the pin retainer plate 12 by itself, and FIG. 4shows a pivot pin 60 by itself. The pin retainer plate has a front 14,rear 16, right side 18, left side 20, top 22, and bottom 24. The pinretainer plate is a retention element that is a flat planar member. Thefront of the pin retainer plate has a front fork 26 that defines a slot28 with opposed flat sides 30 that serves as a first retention facility.The bottom of the pin retainer plate has a bottom fork 32 that defines aslot 34 with opposed flat sides 36 that serves as a second retentionfacility. The bottom fork slot is spaced apart from the front fork slot.The opposed flat sides of the front fork slot are parallel to a firstaxis 86, and the opposed flat sides of the bottom fork slot are parallelto a different second axis 88 angularly offset from the first axis.Thus, the front fork slot is open in a direction away from the bottomfork slot. The bottom fork slot is open in a direction lateral to a lineconnecting the front fork slot and the bottom fork slot. The left sideof the pin retainer plate includes an outwardly protruding dimple 82.

A vertical tab 38 having a front 40, rear 42, right side 44, left side46, top 48, and bottom 50 is attached by the bottom left side to therear 16 of the pin retainer plate 12. A rear fork 52 is attached to thetop left side of the vertical tab. The rear fork defines a curved slot54 that extends between an elongated top tooth 56 and a truncated bottomtooth 58. When the pin retainer plate is installed, the selector pin 106is received within the curved slot in the rear fork.

The two pivot pins 60 shown enlarged in FIG. 2 are identical. Each pivotpin has a head 62, and an enlarged diameter end portion/retentionportion 64 that includes a second cylindrical portion adapted to bereceived in an aperture defined by the receiver 100, tapered portion 66,a first smooth cylindrical body portion 68, end 70, and a pivot pin axis84 defined by the cylindrical body portion. The head defines a toolinterface, which is a slot 72 for a flat head screwdriver in the currentembodiment, but can be any suitable tool interface including Phillips,hexagonal, and hexalobular internal. The forward pivot pin pivotallybears a hammer 116 (shown in FIGS. 1 and 1A), which is a moving actionpart defining a bore 118 that closely receives the smooth cylindricalbody portion. The rearward pivot pin pivotally bears a trigger 120,which is a moving action part defining a bore (not visible) that closelyreceives the smooth cylindrical body portion. The enlarged diameter endportion of each pivot pin defines a first slot pair 74 having a firstflat surface portion and a second flat surface portion (flats 76) withthe second flat surface portion opposed and parallel to the first flatsurface portion and spaced apart from the first flat portion by aspacing greater than a diameter of the cylindrical body portion. Theenlarged diameter end portion of each pivot pin also defines a secondslot pair 78 having a third flat surface portion and a fourth flatsurface portion (flats 80) with the fourth flat surface portion opposedand parallel to the third flat surface portion and spaced apart from thethird flat portion by a spacing greater than a diameter of thecylindrical body portion. The slot pairs are perpendicular to the pivotpin axis and are rotationally offset 90° from each other, with the firstslot pair being located closer to the head than the second slot pairsuch that the second slot pair is linearly offset along the length ofthe pivot pin from the first slot pair. The first flat surface portionis non-concentric with the pivot pin axis 84 such that the pin isprevented from rotating about the pin axis with respect to the frame.The retention portion that defines the flat surface portions ispositioned between the first and second cylindrical portions.

FIGS. 5 and 8 illustrate the improved firearm pin retainer plate andpivot pins 10 of the present invention. More particularly, the firearmpin retainer plate and pivot pins are shown installed in theframe/receiver 100 of the rifle 114. The receiver has a left side wall102, which has a planar portion, and a right side wall 108, which definean internal space between them that receives the hammer 116 and trigger120. The firearm pin retainer plate 12 has a flat body portionoverlaying the planar portion of the left side wall of the receiver.Because so many variations of the AK-47 rifle have been constructed, theside wall of the receiver can have a thickness ranging from 0.035 inchto 0.081 inch. The dimple 82 (not visible) provides an interference fitby pushing the pin retainer plate 12 inward away from the side wall. Asa result, the pins 60 are effectively pulled into the receiver by thepin retainer plate. The front fork slot 28 and bottom fork slot 34engage a selected slot pair 74 or 78 on each pin depending upon thereceiver side wall thickness.

For a receiver having a side wall thickness in the lower or narrowerhalf of the range, the fork slots engage the first slot pair 74 that isclosest to the head 62 of the pivot pin. For a receiver having a sidewall thickness and the upper or wider half of the range, the fork slotsengage the second slot pair 78 that is furthest from the head of thepivot pin. The engagement of the flat sides 30, 36 of the fork slotswith the flats 76 or 80 of the pivot pins acts like a wrench andprevents the pins from rotating with respect to the receiver. The forkslots' engagement with two pins with the fork slots being angularlyoffset also prevents the pin retainer plate from rotating with respectto the receiver. As a result, the only rotational motion is between thehammer, trigger, and their respective pivot pins, which prevents wear onthe receiver pin axis apertures 110, 112 in the right side wall of thereceiver that receive the smooth cylindrical body portions of the pivotpins and the pin axis apertures in the left side wall of the receiver(not visible).

FIG. 6 illustrates the firearm pin retainer plate 12 of the presentinvention. More particularly, the pin retainer plate is shown in theprocess of being installed in the receiver 100. The vertical tab 38serves as a leaf spring and enables the truncated bottom tooth 58, whichis a resilient latch portion, to snap over and releasably engage a fixedelement on the frame/receiver, which is the safety selector pin 106 ofthe installed safety selector 104. The pin retainer plate is anelongated member, and the resilient latch portion is on an end of theretention element opposite the first retention facility (the front forkslot 28). As a result, the safety selector can be installed first,followed by the two pins 60 with the trigger 120 and hammer 116 asrequired by some semi-automatic and all fully automatic variants of theAK-47 rifle. Subsequently, the tool interface 72 on the head 62 of theforward pin is used to orient a selected slot pair 74 or 78 to bereceived within the front fork slot 28. Then, the tool interface 72 onthe head 62 of the rearward pin is used to orient a selected slot pair74 or 78 to be received within the bottom fork slot 34. Finally, therear fork slot 54 is snapped over the safety selector pin as previouslydescribed to secure the pin retainer plate within the receiver.

FIG. 7 illustrates the left side wall 102 of the receiver 100 of thepresent invention. More particularly, the head 62 of each pivot pin 60protrudes from the left side wall of the receiver through pin axisapertures (not visible), which permits the tool interface 72 to beaccessed from outside the receiver. Thus, the orientation of each pivotpin can be controlled to orient a selected slot pair 74, 78 of the pivotpins with the flat sides 30, 36 of the front fork slot 28 and bottomfork slot 34 during installation of the firearm pin retainer plate 12.

In the current embodiment, the firearm pin retainer plate has athickness of 0.032 inch. The first slot pair is 0.055 inch from thehead. The second slot pair is 0.080 inch from the head. The top tooth ofthe rear fork has a length of 0.480 inch, the bottom tooth of the rearfork has a length of 0.265 inch and the rear fork tooth has a radius of1.100 inch.

While a current embodiment of a firearm pin retainer plate and pivotpins has been described in detail, it should be apparent thatmodifications and variations thereto are possible, all of which fallwithin the true spirit and scope of the invention. With respect to theabove description then, it is to be realized that the optimumdimensional relationships for the parts of the invention, to includevariations in size, materials, shape, form, function and manner ofoperation, assembly and use, are deemed readily apparent and obvious toone skilled in the art, and all equivalent relationships to thoseillustrated in the drawings and described in the specification areintended to be encompassed by the present invention. For example, theslot pairs on the pins could instead be a single flat or non-cylindricalsurface, and the opposite sides of the fork flats that serve as a wrenchelement could engage the flat and an opposite point on the cylindricalsurface.

Therefore, the foregoing is considered as illustrative only of theprinciples of the invention. Further, since numerous modifications andchanges will readily occur to those skilled in the art, it is notdesired to limit the invention to the exact construction and operationshown and described, and accordingly, all suitable modifications andequivalents may be resorted to, falling within the scope of theinvention.

I claim:
 1. A firearm comprising: a frame defining an internal space; amoving action part defining a bore and connected to the frame within thespace; a pivot pin connected to the frame and to the action part suchthat the action part pivots with respect to the frame; the pivot pinhaving a cylindrical body portion closely received in the bore anddefining a pin axis; the pivot pin having a first flat surface portion;and a retention element connected to the frame within the space andhaving a first retention facility adapted to engage the first flatsurface portion to prevent rotation of the pin with respect to theframe.
 2. The firearm of claim 1 wherein the pin has a second flatsurface portion opposed to the first flat surface portion and the firstretention facility defines a slot having opposed edges operable toengage the first and second flat surface portions.
 3. The firearm ofclaim 2 wherein the opposed flat surface portions are parallel to eachother.
 4. The firearm of claim 3 wherein the opposed flat surfaceportions are perpendicular to the pin axis.
 5. The firearm of claim 1wherein the retention element is a flat planar member.
 6. The firearm ofclaim 1 wherein the retention element has a second retention facilityspaced apart from the first retention facility and adapted to engage asecond pin to prevent rotation of the retention facility with respect tothe frame.
 7. The firearm of claim 6 wherein the first retentionfacility has opposed side edges parallel to a first axis, and the secondretention facility has opposed side edges parallel to a different secondaxis angularly offset from the first axis.
 8. The firearm of claim 6wherein the first retention facility has a slot open in a direction awayfrom the second retention facility
 9. The firearm of claim 8 wherein thesecond retention facility has a slot open in a direction lateral to aline connecting the first retention facility and second retentionfacility.
 10. The firearm of claim 1 wherein the frame includes a planarportion and the retention facility has a flat body portion overlayingthe planar portion of the frame.
 11. The firearm of claim 1 wherein theretention facility has a resilient latch portion adapted to releasableengage a fixed element on the frame.
 12. The firearm of claim 11 whereinretention element is an elongated member, and the resilient latchportion is on an end of the retention element opposite the firstretention facility.
 13. The firearm of claim 1 wherein the pivot pin hasan enlarged end portion adjacent to the cylindrical body portion anddefining the first flat surface portion.
 14. The firearm of claim 13wherein the enlarged end portion defines a second flat surface portionspaced apart from the first flat surface portion by a spacing greaterthan a diameter of the cylindrical body portion.
 15. The firearm ofclaim 2 including third and fourth flat surface portion spaced apartfrom each other, rotationally offset from the first and second flatsurface portions, and linearly offset along the length of the pivot pinfrom the first and second flat surface portions.
 16. A pivot pin for afirearm having a frame comprising: a first elongated cylindrical portionadapted to receive a pivoting firearm part; the elongated cylindricalportion defining a pin axis; the pin having a first retention portionadjacent to the elongated cylindrical portion; the retention portionhaving a first surface portion adapted for engagement by a retentionelement connected to the frame; the first surface portion beingnon-concentric with the pin axis such that the pin is prevented fromrotating about the pin axis with respect to the frame; the pin having asecond cylindrical portion adapted to be received in an aperture definedby the frame; and the first retention portion being positioned betweenthe first and second cylindrical portions.
 17. The pivot pin of claim 16wherein the first surface portion is a flat surface.
 18. The pivot pinof claim 16 wherein the pivot pin has an enlarged end portion adjacentto the second cylindrical portion.
 19. The pivot pin of claim 16including a second retention portion between the first and secondcylindrical portions, the second retention portion having a secondsurface portion being non-concentric with the pin axis, the secondretention portion having a different location along the length of thepin from the first retention portion.
 20. The pivot pin of claim 19wherein the second surface portion is angularly offset from the firstsurface portion.